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            <h2 class="title" style="clear: both"><a id="txnindices"></a>Secondary Indices with Transaction Applications</h2>
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      <p>
            You can use transactions with your secondary indices so long as you

            <span>
                open the secondary index so that it supports transactions (that is,
                you wrap the database open in a transaction, or use auto commit,
                in the same way as when you open a primary transactional database).
            </span>

            
                
            <span>
                In addition, you must make sure that when you associate the
                secondary index with the primary database, the association is
                performed using a transaction. The easiest thing to do here is
                to simply specify <code class="literal">DB_AUTO_COMMIT</code> when you
                perform the association.
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      <p>
            All other aspects of using secondary indices with transactions are
            identical to using secondary indices without transactions. In
            addition, transaction-protecting 
                <span>
                    cursors opened against secondary indices is performed in
                    exactly the same way as when you use transactional cursors
                    against a primary database. 
                </span>
                
                    See <a class="xref" href="txncursor.html" title="Transactional Cursors">Transactional Cursors</a> for details.
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      <p>
            Note that when you use transactions to protect your database writes, your secondary indices are protected from
            corruption because updates to the primary and the secondaries are performed in a single atomic transaction.
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      <p>
            For example:
        </p>
      <pre class="programlisting">#include &lt;db_cxx.h&gt;

...

// Environment and primary database open omitted
...

Db my_index(&amp;envp, 0);    // Secondary

// Open the secondary
my_index.open(NULL,              // Transaction pointer
              "my_secondary.db", // On-disk file that holds the database.
              NULL,              // Optional logical database name
              DB_BTREE,          // Database access method
              DB_AUTO_COMMIT,    // Open flags.
              0);                // File mode (using defaults)

// Now associate the primary and the secondary
my_database.associate(NULL,             // Txn id
                      &amp;my_index,        // Associated secondary database
                      get_sales_rep,    // Callback used for key
                                        // extraction. This is described 
                                        // in the Getting Started guide.
                      DB_AUTO_COMMIT);  // Flags </pre>
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